Poly(urethane-dimethylsiloxane) (PU-PDMS) anionomers with increased hydrophobicity and fixed amount of elastic segments (51 wt %) at 3- and 4-stage methods were obtained. The anionomers were synthesized from isophorone diisocyanate, poly(oxytetramethylene)diol, and alpha,omega-polydimethylsiloxanediol (PDMS). 2,2-bis(hydroxymethyl)propionic acid (DMPA) was used as ionic center. The anionomers were extended with ethylenediamine (EDA) in water. H-1 NMR and IR methods were employed to confirm the chemical structures of the anionomers. Suitable defined structural factors kappa and alpha were calculated on the basis of selected bands of the spectra. The factors were employed to perform detailed quantity and polarity analysis of the anionomers structures. The free-surface energy (FSE) of the anionomers was evaluated on the basis of physical model by Owens and Wendt. The effect of chemical structures on polarity of the materials was discussed. It Was found that the FSE and its polar and dispersive components distinctly decrease with the increasing polisiloxane content in the anionomer chain. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3488-3500, 2008